Arc tube mount



Sept. 6, 1960 H. D. FRASER ET AL ARC TUBE MOUNT Filed Oct. 30, 1957 HUGH D. FRASER MA MELVIN C. UNGLERT ATT'O ZN EV.

United States Patent ARC TUBE MOUNT Hugh D. Fraser, West Caldwell, and Melvin C. Unglert,

Wyckoif, Nl, assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Fennsylvania Filed Oct. 30, 1957, Ser. No. 693,395

7 Claims. (Cl. 313-25) This invention relates to high-pressure, electric-discharge devices and, more particularly, to an improved arc tube mount construction for a high-pressure, electricdischarge device.

High-pressure, mercury-vapor lamps are well known and are generally described in US. Patent No. 2,748,303 to Thorington. Such lamps generally comprise an inner arc tube which encloses the mercury discharge during lamp operation and an outer envelope surrounds the inner arc tube. The outer envelope may be left clear or may be coated with a phosphor material.

. One of the most troublesome problems in the manufacture of such lamps is the construction of the arc tube mount and a typical construction is shown in Fig. 1 of the aforesaid patent to T horington. Such a typical mount construction normally comprises a wire frame with metal bridges and the frame and bridges are normally welded together. In addition metal springs, which are also welded to the frame, position the arc tube mount within the outer bulb.- The multiplicity of welds and bending of wires makes such a construction quite expensive and troublesome. For example, in the case of failure of one or more of the welds, the arc tube isapt to slip from its positioning within the outer envelope and cause a lamp failure. Also the bending of wires and the individual welding procedures required to form the mount structure are exacting and expensive.

It is the general object of this invention to avoid and overcome the foregoing and other difficulties of and objections to prior-art practices by the provision of a highpressure, electric-discharge device having a mount which is extremely durable and which will not allow the arc tube to move within the outer envelope, even with failure of one or more of the mount-forming portions.

It is another object to provide a high-pressure, electricdischarge device having an arc tube mount which can be readily and cheaply fabricated on a mass-production basis with a minimum of individual fabrication operations.

It is a further object to provide an assembly incorporating an arc tube and the mount therefor for fabricating a high-pressure, electric-discharge device, wherein the assembly is extremely rugged, inexpensive to fabricate and can be readily handled during lamp fabrication.

The aforesaid objects of the invention, and other objects which will become apparent as the description proceeds, are achieved by providing a high-pressure, electricdischarge device having an arc tube mount which com prises two adjacent metal frames, each of which have two end-connected longitudinal members positioned on opposite sides of the arc tube and spaced apart therefrom. The are tube is provided with seals extending from either end thereof, as is customary, and transverse frame members, which connect across each of the longitudinal members of the frame, supportingly engage the extending seal portions of the arc tube. Desirably, the transverse members which support the arc tube arebent in complementary fashion to conform to the seal portions ice of the arc tube. The metal frames are secured to one another, preferably by spot welding in a plurality of locations, to maintain the frames in their adjacent relationship, even with failure of one or more of the individual welds, for example. The are tube and mount form an assembly which can be readily handled without failure and which provides a very strong construction when incorporated into a lamp.

For a better understanding of the invention, reference should be had to the accompanying drawing wherein:

Fig. 1 is an elevational .view, partly in section, of a high-pressure, mercury-vapor lamp incorporating the improved arc tube mount construction;

Fig. 2 is a side elevation, partly in section, of the lamp as shown in Fig. 1;

Fig. 3 is a fragmentary sectional view taken on the line IIIIII in Fig. l in the direction of the arrows;

Fig. 4 is a sectional view taken on the line IV-IV in Fig. 2 in the direction of the arrows;

Fig. 5 is a sectional view taken on the line V--V in Fig. l in the direction of the arrows;

Fig. 6 corresponds to Fig. 4, but illustrates an alternative embodiment for the arc tube mount construction;

Fig. 7 corresponds to Fig. 5, but illustrates an alternative arc tube mount construction;

Fig. 8 corresponds to Fig. 5, but illustrates a further alternative are tube mount construction;

Fig. 9 is a small-scale elevational view of a still-further alternative arc tube mount construction.

Although the principles of the invention are broadly applicable to any type of electric-discharge device which involves a dual-envelope construction, the invention is usually employed in conjunction with high-pressure, mercury-vapor lamps and hence it has been so illustrated and will be so described.

With specific reference to the form of the invention illustrated in the drawing, the numeral 10 in Figs. 1 and 2 indicates generally a high-pressure, mercury-vapor lamp which comprises a light-transmitting outer envelope 12, which may be fabricated of a vitreous material such as hard or soft glass. The outer envelope 12 has a dome portion 14 which may take the form of a small protrusion which assists in providing support for the arc tube mount. The outer envelope 12 also has a neck portion 16 to which the lamp base 18 is secured and the outer envelope 12 is hermetically sealed at its neck 16 by means of a reentrant stem press 20, as is customary in the art. The outer envelope preferably encloses a nitrogen-gas fill at a pressure of about 500 millimeters, for example, although other inert-gas fills or vacuum could be used if desired. Sealed through the reentrant stem press 20 and electrically connected to the lamp base 18 are two lamp lead conductors 22 .and 24, as is customary, and these are electrically connected to the arc tube 26, as explained in detail hereinafter. The outer envelope may be left clear, if desired, or it may be coated with a phosphor material such as described in the aforementioned Thorington patent, for example.

The are tube 26 is of generally-standard construction and comprises a light-transmitting envelope 28, normally fabricated of quartz, or in some cases Vycor, having seals 30 extending from either end thereof. Arc tube lead conductors 32 are hermetically sealed through the arc tube seals 30 with a conventional ribbon-seal technique and are electrically connected to electrodes 34 operatively disposed within the arc-tube at either end thereof. For purposes of electron-emissivity a thorium sliver, for example, is desirably included as a part of the electrodes 34, which may be fabricated of tungsten, for example, and such electrode constnlctions are well known. A starting electrode 36 is desirably positioned within the arc tube proximate one operating electrode and is connected to the same electrical potential as the opposite are tube electrode through a resistor '38, such as a 15K resistor, as is usual in such lamp designs. The are tube contains a selected charge .of mercury and an inert ionizablegassuch as 20-25 mm. of argon, for example. The mercury charge maybecontrolled such as by'a method as taught. in .UIS. Patent No. "2,755,159 to B ernier et al., .for .example.

'The are tube mount40 which'supports the arc tube in position within (the outer envelopegenerally comprises two .adjacent .metal frames 42 and 44. These metal frames are desirably punched into a predetermined configuration from sheet stock, such as'lO mil nickel-platedironsheet stoek,'forexample. fEach adjacent metal frame generally comprises two 'ilongitudinal members 46 which are positioned on opposite sides of the arc tube 26 and are spaced apart therefrom. 'The longitudinal members 46 of the metal frames .are connected at their ends .for purposes of rigidity and in the embodiment as shown, the upper ends of themetal frames eachhave a configuration similar to that of the ."dome '14 of the outer envelope '12, in order to inhibit anyllateral .motion of the mount 40 Within the outer envelope. Each of the bottom ends of the frame longitudinal members 46 are connected by transverse frame members 'in the embodiment as shown, although the frame .constructionscoirld bemade symmetricaLQif desired, so that .thelbottom frame portions would have configurations similar to the frame top portions which are illustrated in Figs. 1 and 2. Each frame has an upper transverse member 48 and .a'lower transverse member 50 which connectacross each of'the longitudinal members v46 and supportingly engage .the extending seal portions'3'0 of the are mine 26. The metal frames preferably vare .spot welded to one another ina plurality of locations-"52 to maintain themin. adjacent relationship and to secure the arc tube firmly.

' In Fig. 3 is showna-plan view of the upperframe transverse members 4 8 and upper seal portion of the arc tube '26 and as illustrated, the frame transverse members-48 desirably are bent in complementary fashion so. as to conform to the-configurationof the upper seal portion of the arc tube '26 to firmly secure same. Such a construction isillustratedin sectionin Fig. 5 and the lower transverse members '50 vdesirablyhave a similar configuration.

The punched metal frames '42 and 44 may have a fiat cross-sectional configuration, as shown in 'Fig. v4, but it may be desirable topunch the frames so that-they have a non-planar (or as otherwise expressed, multi-planar) cross-sectional configuration. "This serves to increase the frame strengthin a lateral direction. Such anon-planar cross-sectional configuration may take many different forms, butit has been found convenient topunch .a ribbed configuration into the frames and such an alternative embodiment. is shown .in "Fig. 6.

Inthe preferred form of the invention the frame transverse members 48 and 50 are bent .in complementary fashion so as to conform to the configuration of the seal portions 30 of .the .arc tube 26. "The'frame-transverse members, however, need. not conform to .the seal portions of the arc tube, but may be formed so that theframe transverse members are'bent about the arc tubes during fabrication of the mount andarc tube assembly; Such an embodiment is illustrated 'in 'Fig. 7 wherein the spring action of the metal transverse members 48a exert a force on the arc-tube .seals .to maintain same in position. In the preferred form offthe invention the arc-tube seals 30 have been of thepinCh-Wpe so thatthey haveagenerallyflattened .cross sectiona'l -configuration. The seals may also have agenerally-circular cross-sectional configuration,.for example, and such an alternative seal embodiment 30a .is also shown in Fig. 7.

Infabricatingthe arc-.tube and mount assembly, the metalframesare .first punched .out of .thesheet stock as .indicated.hereinbefore. .Twoof the .frames are then placeddn adjacent relationship with .the .arc tube in the desired position and the framesand are tube desirably are clamped into a jig.

The adjacent metal frames are then preferably spot welded in a plurality of locations in order to maintain the arc-tube-securing frames in their adjacent and arc-tube-securing relationship. Desirably the metal frames are welded to one another at least at the corners which are formed by the transverse members and the longitudinal members, but since the multiple spot welds may be accomplished'inone operation with a standard welding jig, many more weldlocations may be provided withoutany --appreciable increase in cost and labor. Simultaneously.thereentrant stem press and lead conductors may be electrically connected to the arc tube mount 40 and one of the lead conductors 22 may be welded directly to-the*mount-40"in orderto 'provide'support and facilitate electrical connection to the .upper electrode of the arc tube. To finish the lamp fabrication, the arc tube lead conductors are welded to the lamp lead conductors, or frame as indicated, the startingresistor welded in place and the-arc tube andmount assembly inserted into the outer envelope until the upper endsof the adjacentframes 42 and 44 contact the dome portion 14 of the outer envelope 12. Thereafter the outer envelope .14is1hermetically sealed by theusual techniques. The .lampbaseis then secured to the neckof the lamp by conventional practices and the lamp lead conductors 22 and 24 electrically connected thereto.

The fabrication of .thelforegoing arc tube and mount assembly is quite simple and only involves a stamping and one main weldingoperation. The'arc tube mount'is extremely rugged and able to withstand the shocks of fabrication and-service betterthan the mount constructions of theprior'art. In addition, even if one or more of the spot welds break, as long as suflicient welds remain intact to maintain the frames comprising the mount in their adjacent'relationship, the arctube will be maintained in position-within the outer envelope and the lamp will function properly.

It willbe recognized that theobjects of the invention have beenachieved byproviding a high-pressure, electric-discharge devicehaving an .arctube mount which is extremely durable and which will not allow the arc tube-to move within the outer envelope, eventhough one or more of the mount-forming welds fail. -In addition, the mount "for the arc tubecanbe readily and cheaply fabricated on a mass-production basis with a minimum of individual fabrication "operations. lThere has also been provided an arc tube and tmount assembly for incorporation into a high-pressure electric-discharge device, whichassembly is extremely ruggedand T0311 be readily handled during lampfa'brication.

As an alternative embodiment, thespotwelds which I maintain the frames in their adjacent relationship may be replacedby rivets"5'4 as shown .inFig. .8. Also, tabs may be provided on the frames 'andthesemaybeerimped over the adjacent frame 'to'secure them together. From the standpoint of cost and performance, however, aspot welding technique is preferred in forming the instant mount.

In the preferred embodiment .ofthe 'arctube mount as described hereinbefore, the longitudinal members 46 of each of the punched metal "frames '42.and 44 are connected .at their ends for purposes ofrigi'dity and additional transverse members connected across .the longitudinal members of the framesandare.conformed'to support the arc tube imposition. As 'an'alternative construction, the end connections .for the 'frame longitudinal members may be efiie'ctediby .the transverse members which also support the arc'tube. Such an alternative embodiment is illustrated in Fig. 9'wherein the frame transverse members 48 'a'nd'50 which support the arc tubealso serve the dual function of'providing end connections for each of the frame longitudinal members 46 to, provide rigidity. Additional support members 56 and 58 may thenbeprovided on'the'frameto cooperate'with the domeportion 1'4 of the outer envelope 1'2and with the lead conductor 22 to support the arc tube mount in position within the outer envelope.

While in accordance with the patent statutes one bestknown embodiment of the invention has been illustrated and described in detail, it is to be particularly understood that the invention is not limited thereto or thereby.

We claim:

1. A high-pressure electric-discharge device comprising: a light-transmitting outer envelope; an inner lighttransmitting arc tube having a seal extending from either end thereof and a mount supported within said outer envelope and supporting said are tube in position within said outer envelope; said mount comprising, two adjacent metal frames each having longitudinal members positioned on opposite sides of said are tube and spaced apart therefrom, transverse members connecting across each of the longitudinal members of said frames and supportingly engaging the extending seal portions of said arc tube, and said metal frames secured to one another in a plurality of locations to maintain said frames in adjacent relationship.

2. A high-pressure electric-discharge device comprising: a light-transmitting outer envelope; an inner lighttransm-itting arc tube having a seal extending from either end thereof; and a mount supported within said outer envelope and supporting said are tube in position within said outer envelope; said mount comprising, two adjacent generally-flat metal frames each having end-connected longitudinal members positioned on opposite sides of said are tube and spaced apart therefrom, transverse mem- \bers connecting across each of the longitudinal members of said frames and supportingly engaging the extending seal portions of said are tube, and said metal frames welded to one another in a plurality of locations to maintain said frames in adjacent relationship.

3. A high-pressure electric-discharge device comprising: a light-transmitting outer envelope; an inner lighttransmitting arc tube having a seal extending from either end thereof; and a mount supported within said outer envelope and supporting said are tube in position Within said outer envelope; said mount comprising, two adjacent generally-flat metal frames each having endconnected longitudinal members positioned on opposite sides of said are tube and spaced apart therefrom, transverse members connecting across each of the longitudinal members of said frames and supportingly engaging the extending seal portions of said are tube, said transverse members bent in complementary fashion conforming to the seal portions of said are tube, and said metal frames welded to one another in a plurality of locations to maintain said frames in adjacent relationship.

4. A high-pressure electric-discharge device comprising: a light-transmitting outer envelope; an inner lighttransmitting arc tube having a seal extending from either end thereof; and a mount supported within said outer envelope and supporting said are tube in position within said outer envelope; said mount comprising, two adjacent metal frames having a non-planar cross-section to increase the frame strength in a lateral direction, each of said frames having two end-connected longitudinal members positioned on opposite sides of said are tube and spaced apart therefrom, transverse members connecting across each of the longitudinal members of said frame and supportingly engaging the extending seal portions of said are tube, said transverse members bent in complementary fashion conforming to the seal portions of said are tube, and said metal frames welded to one another in a plurality of locations to maintain said frames in adjacent relationship.

5. A high-pressure electric-discharge device comprising: a light-transmitting outer envelope; an inner lighttransmitting arc tube having a seal extending from either end thereof; and a mount supported within said outer envelope and supporting said are tube in position within said outer envelope; said mount comprising, two adjacent metal frames having a ribbed cross-section to increase the frame strength in a lateral direction, each of said frames having two end-connected longitudinal members positioned on opposite sides of said arc tube and spaced apart therefrom, transverse members connecting across each of the longitudinal members of said frame and supportingly engaging the extending seal portions of said are tube, said transverse members bent in complementary fashion conforming to the seal portions of said are tube, and said metal frames welded to one another in a plurality of locations to maintain said frames in adjacent relationship.

6. An assembly for insertion into an open'ended lighttransmitting envelope for an electric-discharge device, said assembly comprising an arc tube having a seal extending from either end thereof, an arc-tube mount for supporting said are tube in position within said outer envelope, said mount comprising two end-connected adjacent metal frames each having two longitudinal members positioned on opposite sides of said are tube and spaced apart therefrom, transverse members connecting across each of the longitudinal members of said frames and supportingly engaging the extending seal portions of said are tube, said transverse members bent in complementary fashion conforming to the seal portions of said are tube, and said metal frames welded'to one another in a plurality of locations to maintain said frames in adjacent relationship.

7. A high-pressure electric-discharge device comprising: a light-transmitting outer envelope having a dome and a neck; a base secured to the neck of said outer envelope; an inner light-transmitting arc tube longitudinally disposed within said outer envelope and having a. seal enclosing an arc-tube lead conductor extending from either end thereof; lamp lead conductors electrically connecting to said base, sealed through said outer envelope and operatively connecting to said inner arc tube; and a mount supporting said are tube in position within said outer envelope and facilitating electrical connection for said are tube; said mount comprising, two adjacent generally flat metal frames each having two end-connected longitudinal members positioned on opposite sides of said are tube and spaced apart therefrom, transverse members connecting across each of the longitudinal members of said frames and supportingly engaging the extending seals of said are tube, said transverse members bent in complementary fashion conforming to the seal portions of said are tube, said metal frames welded to one another in a plurality of locations to maintain said frames in adjacent relationship, the portions of said adjacent frames adjacent the dome of said outer envelope cooperating therewith to provide frame support, one of said lamp lead conductors connecting to the portion of said frame proximate the neck of said lamp to provide frame support within said outer envelope, and the lead conductor of said are tube which is closest the dome portion of said lamp electrically connecting to said frame.

References Cited in the file of this patent UNITED STATES PATENTS 2,171,234 Freeman Aug. 29, 1939 2,175,361 Reger et a1. Oct. 10, 1939 2,704,879 Diggle Mar. 29, 1955 2,748,303 Thorington May 27, 1956 2,749,461 Hierholzer et al. June 5, 1956 2,830,210 Jenne et al. Aug. 8, 1958 2,848,641 Peterson Aug. 19, 1958 2,879,449 Macksoud Mar. 24, 1959 

